Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1887-05-05
HOW CREAM RISES.
Many Points That Are But Imperfecffv
Understood by Most Dairymen.

Many Points That Are But Imperfecsiy
Understood by Most Dairymen.
The secret of raising cream consists
in suddenly cooling the milk. In
round numbers we are told that milk
is eighty-seven per cent. water, four
per cent sugar, and the same quantity
of butter fats. The fat is the part
which we wish to separate from the
milk. to manufacture into butter.
Milk is little heavier than water.
probably on account of the sugar il
contains. 1t also heats and cools much
slower than water, hence it is what
our scientific friends call ssbad con-
ductor.''
If milk, which is composed so large.
ay of water, heats and cools more
slowly than water, it can only be &C.
counted for by the fact that the re-
naming thirteen per cent, which con.
tains the butter fat, holds heat,
or keeps the milk from cooling
as soon as water, under pre-
cisely similar conditions. We know
that milk or water will shrink in cool
ing, at least we know that the power
OF steam is due to the expansion of
water caused by heat. / find that milk
contracts so it weighs about half an
ounce more to the gallon at forty-eight
degrees than at ninety-eight degrees.
To prove this last statement that
water is better conductor of heat
than milk, put one hand into a pail of
water at temperature of thirty-two
degrees, and hold the other in pail of
milk, of the same temperature You
will find that the hand in the water
will feel a sensation of cold before the
one in the milk.
Take a can of milk eight and hall
inches in diameter, and twenty inches
deep. Place this in vessel of water
OF the same depth, which contains as
much water as the other does of milk.
The temperature of the milk being
ninety-eight degrees. and of the
water forty-eight degrees. In a
short time the thermometer
will show US that the milk and the
water are both of the same temper
sature, or seventy-three degrees. the
water having taken part of the heat
from the milk, thereby increasing it's
own temperature, and decreasing that
of the milk. If a can of milk were
placed in large quantity of water, as
in a well, there would be so much more
water than milk that the milk would
be reduced to the temperature of the
water without sensibly decreasing the
temperature of the water. It would be
found that the temperature of the milk
had not only been decreased, but that
the cream had risen to the surface, If
the milk had been left long enough in
the water. Why? Water on cooling
shrinks, and becomes denser-that is,
weighs more, cubic foot for foot.
Now, when the milk is placed in
the cold water it is gradually cooled.
but it does not cool evenly. As said
before, eighty-seven per cent of the
milk is water, and this cools more
rapidly than the other thirteen per
cent. of fats, etc., and consequently
shrinks and becomes heavier. If we
put two liquids in vessel together,
the heavier one will sink to the bottom,
and the lighter one rise to the top
just so the watery part of the milk set
ties to the bottom of the can, and the
lighter part, which does not cool so
rapidly as the water, and therefore
shrinks slower, rises to the top. IF this
reasoning is true, it is very important
that it be well understood, so that the
underlying principle may be taken adj
vantage of by the different farmers
whose conveniences for their work vary
go widely.
There is one point which must not be
overlooked in the above reasoning.
We have said that cooling milk causes
it to shrink and become heavier, but
the temperature must never be below
thirty-nine degrees. If have not for
gotten the valuable lesson that water
shrinks as it cools to thirty-nine de
grees, and then begins to expand i
cooled further. Cooling below thirty
cine degrees is, therefore, detrimental
have made this study many years
and came to the conclusion here giveI
long ago, and acted upon it. This study
has been to perfect the system of cream
raising that can be done on th.
farm. One that the farm provide:
for the year round without even th'
aid of ice, though ice is a valuable helI
in hot weather. The temperature o.
deep wells is about forty-eight, an(
thisawi1 answer very satisfactorily fol-
cream raising, provided we do not de
lay In straining and setting the cans
in this well water, and do not allow
the water to warm up, which it vii
surely do if there is not a large enough
quantity of it or if it is not oftel
changed. The water will conduct th'
heat out of the milk into itself just a
surely as it will conduct the heat GU
of red-hot iron placed in it. c
Curtis. IN Prairie Farmer.
Tan1aIe Parties in the West.